Braking system for vehicles



Aug. 27, 19350 c. CHR IS'i'ENSEN 5 BRAKING SYSTEM FOR VEHICLES Filed Dec. 24, 1931 Patented-Aug; 21, 1935 7 3,012,258 muss sxs'rm roa vamcna a. Ohflatcmen, San Francisco, cam..- to Besler,l"la lnileld,N. J.

Clarence William].

application 24,

1931, Serial No. 583,101

' 'a cum; (Cl. sea- 20) This invention relates to braking systems and -apparatus or the servo-motor. type for vehicles and the like, and particularly to systems and apparatus adapted for use in connection with the brakes on truck trailers, for example, in which a control valve upon'the'truckis arranged to control thebrakeson the trailerthroughtheinstrumentality of a relay valve onthe traileroperatively connected to the first mentioned valve In braking systems for truck trailers and other installations where the servo-.motor is relatively far removed from the operator's position, a relayvalve adjacent the servo-motor is employed to obviate the time delay encountered where the servo-motor is directly controlled by the control valve at the operator's position. 18.811011 systems, the main control valve is operative to control the relay valve, which in turn eitects rapid and accu- 7 rate energizatiqn and release oithe servo-motor.

The relay valve may be controlled by the main control valve, for example, by means of a fluidpressure connection between-said valves, so that the adjustment of the relay valve and thecorresponding operation or the servo-motor is dependent upon the pressure of the fluid in said conr nection. In systems of this charagter, diiiiculty is controlling means, the. adjustment of which corresponds to the extent of application or the brakes. 'lfhe'controlling means, in the preferred embodiment of the invention, comprises an adiustable valve member movable between '0 and 11 positions and provided witha restricted byu or bleeding passage soarranged that the pressure in the fluid connection extending to'the motor brakes, the latter including. main control valve, relay valve, motor and brake;

relay valve varies in substantially direct ratio to the extent or movemento! .said'valve Since thepressure; applied-to the relayj-valvede-' terminesthe degreeorenergizationoitheservocorresponds tothe Vadiustment of the movable valve member.

Other objects and advantages of the invention will appear from the iollowing description of the, embodiment thereof shown on the accompanying drawing,whereln:

Fig.1 isadiagrammaticviewori'themtem, servo-- Fig. 2 is a detail view of the relay valve, the

casing, diaphragm and valve piston being shown in section with the diaphragm and piston in their normal or balanced positions in which the valve ports are closed; 1

Fig. 3 is a detail view oithe piston 'of valve;

Fig. 4' is an elevational-view or the valve body I of the main control valve with \top movable member groove-dotted in position; and

Fig. 5 is a fragmentary view of the top movable member of the main control valve.

The braking system shown by way of example in the drawing comprises a main control valve vided with angularly disposed ports a. s and lo,

the port 8 being connected preferably through a check valve II and, if desired, a suitable reservoir to a source of reduced pressure, such as the intake manifold of the engine. The ports 9 and iii are. connected to atmosphere and to the relay valve 3, respectively. A movable valve member i2 controlled by the handle 2 is arranged upon the body portion 1 and is provided with a passage or groove i2a-arranged to cooperate with the I port openings 8, S and Ill, and to interconnect the port in with the port a or the port a, or both in the relay of the relay valve 3. Apressure gauge ll con ;nectedtotheconnection limaybearrangedadiacent the main control valve i to apprise the operator ofthe degree of 'energimtion of the brakes I 'upon the trailer. 7

,Any suitable form of relay, valve 3 which is responsive to presu're and operative to controlthe servo-motor I may be employed. One form ofvalve whichmaybeutilized isshownindetail' in-l 'ig. 2 and comprises a. hollow casing 18. one

'is threaded 'or otherwise adapted to receive the pipe connection l3 tpplacethe-same incommu'nication with one side of the 2|. The diaphragmis arranged to control theposition o! the'movable valve member II, for examplein the 'endofwhichisclosed byacapmemberil. A

4 of the main control valve I is provided form of a piston arranged to slide in the hollow casing it, The piston 2| is flexibly connected as indicated at 22 to the diaphragm 20.

As shown in Fig. 3, the valve member 2| has a reduced end portion 23 with openings 24 therein to provide communication between the inner side of the diaphragm and the interior of the valve member 2 I. The casing I8 is provided with port openings 25 and 26 arranged to cooperate with the valve member 2 I, whereby the pipe connection 21 will be connected either to the port 25 and reservoir'28 or the port 26 open to the atmosphere, depending upon the position of the valve member'2|-., It will be apparent that the position of the valve member 2| and consequently the pressure in the connection 21 leading to the servo-motor 4 depends upon the relative pressures direction as to equalize the pressure in the con nection 21.. The port opening 25, being connected to a suitable source of reduced pressure:- controls the application of the brakes whereas the port opening 28 is open to' the atmosphere and controls the release of the brakes.

As shown in Figs. 4 and 5,- the valve mem r l2 th a passage or groove I21: of such shape that upon the controlling movement of thevalve member l2 the pressure in the fluid-pressure connection I! is only reduced substantially in proportion to the extent of such movement, instead 0! being suddenly lowered to a minimum value when communlcation is established with the suction intahe port I. A

It is obvious from the construction of the movable valve member II that in the on position, the port ll is connected to port 2 andpor't l is blanked oil and brakes will be full on. Similarly in the oil position, the port ,llJ-is connected toport S,tlie'portlisblankedofl andbrakeswill be full oil. In intermediate pomtions, the port It is connected to both ports I and l, and,.the resultant reduced pressure in line I! will depend upon the diflerence between the rate at which air is drawn out of groove Ila and supplied to groove I21; and the brakes will be applied in proportion to the reduction. Moving thev operating handle in the "on" direction will increase the oriflce produced by the groove I241 and port I and decrease the oriilce produced between the groove Ho and port 8 thus lowering the pressure in the line is and producing greater braking eilort, Moving the control handle in the "011 direction will produce the opposite result and decrease the braking eiIort.

In this manner, the pressure of the fluid in the connection l3 may be accurately and readilycontrolled in accordance with-the position 01' the handle 2, thereby eflecting a similar partial energization or release or servo-motor l as above described. Inaddltion, the gauge indicates to the operator the pressure variation in the controlling system which is a measure of the degree of energization of the brakes on the trailer.

Various modifications oi the structure shown and described herein will occur to those skilled in the art and are intended to come within the a scope of the present invention it within the terms of the appended claims.

I claim: 1. In 'a braking system for a vehicle comprising a servo-motor brake, a relay valve, for con- 7 trolling the same, and fluid-pressure means for controlling said relay valve; a main valve associated with said fluid-pressure means being provided with relatively movable valve members,

. one of said members having ports and another or said members having a restricted passage to movement of said valve members.

2. In a braking system for a vehicle comprisregister to .a variable extent with said ports to 10 eifect a gradual variation of pressure upon the relay valve determined by the extent of relative ing a servo-motor brake, a relay valve for enerl5- sizing said servo-motor brake to an extent-depending upon the adjustment of said valve, and

a fluid-pressure connection to said relay valve; a main control valve associated with said fluidvalve member having an elongated groove formed therein of varying cross-section, and means cooperating with said groove whereby the pressure in said fluid-pressure connection varies in sub- ;pressure connection and embodying a movable Q stantially direct ratio to the extent of movement 25 havingarestrictedearrangedtoregister a variable extent with said ports to eflect a gradualjvariation of pressure upon the relay valve determined by the extent of movement 0! said movable valve member.

4. In abraking system for a vehicle comprising a servo-motor brake, a source of fluid pressure for operating the same, a-relay valve controlling the connection between said source and the servo-motor brake and fluid-pressure means including a main control valve !or controlling said relay valve, said main control valve emy ns a casing provided with three spaced ports leading to said source of fluid pressure, .to atmosphere and to said relay valve, respectively,

and a movable valve member arranged to connect all of said ports simultaneously and in other positions to connect said relay valve port to the other ports individually.

5. In a braking system for. a vehicle comprise ing a source of fluid pressure, a servo-motor brake, arelay valve for controlling the same and fluid-pressure means including a main valve for controlling said relay valve, said main valve being provided with a movable valve member adapted to connect said relay valve simultaneously to atmowhere and to said source of fluid pressure through variable orifices. a

6. In a braking system for a vehicle compriscontrolling the same; a movable member having a fluid passage formed therein or varying crosssection, and fluid pressure connections cooperat ing with the said passage of said member and .ing a servo-motor brake,-and a relay valve for said relay valve whereby the latter will function in substantially direct' ratio to the extent of movement of said movable member to effect a corresponding brake application.

; cmnsncns. 

